Vehicles such as semi trailers are often removed from locations at undesired moments. They can be stolen from a company yard, parking lot or truck stops. This situation can also happen at a loading dock. Some reports say that more than 30 billion dollars worth of goods disappear with stolen semi trailers. Some places secure their area with fences and gates, some may also have guards to help control the security. There are no reported systems to secure a specific vehicle in those areas.
Loading and unloading operations are hazardous for forklift trucks entering and exiting a truck trailer. It is imperative that a truck remain immovably docked at the loading dock to prevent moving fork lifts from falling through the space created if a truck trailer moves.
There are two known types of restraint systems: ICC bar restraint systems to prevent the truck from moving away from the dock, and wheel restraint systems. However, while the first system is suitable for a majority of trailers, there are several configurations of trucks that cannot be secured by such ICC bars. Besides, ICC bars are built to absorb a rear impact with another truck and are not designed to resist a strong pulling force. In view of this fact, this system does not prevent the truck from moving away from the loading dock. The second category includes manual and mechanical chocks. Manual placement of a chock presents different problems, such as chocks which may be displaced, damaged, lost, or stolen. They also may slip on icy, oily or dusty surfaces and are often difficult to remove from their operational position because they may be wedged very tightly under the trailer's wheel. Very often, chocks are removed before the loading operation is complete, thus creating a dangerous situation where the vehicle can depart prematurely or slide away from the dock as heavy fork lifts enter the trailer. Also, docked trailers can be stolen mostly after business hours. In a lot of cases, trailers are a target for theft as they are loaded with valuables.
Mechanical wheel chock systems are more effective than manual chocks. They also are not very easy to service and often have to travel a substantial distance from storage into operative position. Other mechanical chocks which are mounted on the surface may be affected by winter and become an obstacle during snow removal. They also may interfere with the tail gate of the truck or truck's undercarriage, and are inoperable with many types of vehicles.
One mechanical wheel chock restraint system known in the art and which is effective is that disclosed in U.S. Pat. No. 7,032,720 the contents of which are hereby incorporated by reference.